Stealthier Inter-packet Timing Covert Channels

Sebastian Zander (1) , Grenville Armitage (1) , Philip Branch (1)

1 Swinburne University of Technology [Melbourne]

Covert channels aim to hide the existence of communication. Recently proposed packet-timing channels encode covert data in inter-packet times, based on models of inter-packet times of normal traffic. These channels are detectable if normal inter-packet times are not independent identically-distributed, which we demonstrate is the case for several network applications. We show that ~80% of channels are detected with a false positive rate of 0.5%. We then propose an improved channel that is much harder to detect. Only ~9% of our new channels are detected at a false positive rate of 0.5%. Our new channel uses packet content for synchronisation and works with UDP and TCP traffic. The channel capacity reaches over hundred bits per second depending on overt traffic and network jitter.

Mots clés: Covert Channels; Steganography; Inter-packet Times

Domaines: Informatique [cs]; Réseaux et télécommunications [cs.NI]

Sebastian Zander, Grenville Armitage, Philip Branch. Stealthier Inter-packet Timing Covert Channels. 10th IFIP Networking Conference (NETWORKING), May 2011, Valencia, Spain. pp.458-470, ⟨10.1007/978-3-642-20757-0_36⟩. ⟨hal-01583422⟩